In melting furnaces, especially glass melting furnaces, electrodes are arranged in groups, within separate zones, with each group of opposed electrodes connected across individual outputs of a power supply. The electrode groups may be two opposed electrodes or three electrodes in a group or other variations. In the prior art, set forth in U.S. Pat. No. 3,440,321, a Scott T connection is used to energize two groups of opposed electrodes within a furnace. Also shown in that same patent are two zones of two groups each, with each of the adjacent groups connected to the Scott T connection.
A problem with the prior art is that adjacent electrode groups such as the groups of electrodes shown in U.S. Pat. No. 3,440,321 must be widely physically separated to prevent crossfiring and undesired current paths between the electrodes of different groups. It has therefore been a problem to increase the number of heat producing zones within a furnace and the amount of heat which can be placed in an electric furnace has been limited.